A Series - 1275 - Tap Size Set?

[Skeete]

I am about to embark on rebuilding a Pre-A+ Series 12g1279 Engine Block, 12g940 head and a 22g1128 gearbox.
I also have a 22g1832 gearbox, but am undecided in which to use.

The setup as far as I can tell, is completely original, all bores and sizes match up, so I doubt much work (if any) was ever performed on the engine, but you never know.

I want to go over the entire setup first with taps to make sure all of the threads are in good shape, but for the life of me I cannot find a guide on all of the bolt sizes. Does anyone have a comprehensive list available that they can share?

Thanks

[woodypup59]

Get yourself a set of UNF and UNC taps from 3/16 to 1/2" .

Most threads into castings (alloy or iron) will be UNC.

[Herbert]

actually all bolts/studs going into ally are UNC all other bolts/nuts are UNF.
Gearbox to Block (lower part) are 5/16 UNF
Water pump bolts are UNF
Tappet chest bolts are UNF.
Manifold studs are UNC

[Peter Laidler]

Like Woody says above. You gets what you pays for with these things, so get high quality (I'm going to suggest Snap-On) and they'll last you a lifetime. I've slogged mine to death 10 times over and chipped one or two. But the snap-on man changes 'em without a question

[Oneball]

Manifold studs are UNF I think
Thermostat UNC
Rocker posts UNC
Heater tap UNF

[Herbert]

yes, you are right, my mistake that I didnt eloquate...its the studs that go on the inlet manifold....Definitely get Snap-on ones, if they break or go dull Snap-On will replace them FOC

[MiNiKiN]

I have a list of bolt sizes:
one list is more comprehensive but partly German - you'll need Google translate (N.B. LIMA is generator, not gonna find that in the dictionary)
The other list is limited to the engine, but in English.

[Spider]

For this purpose I would recommend against using taps.

You aren't cutting new threads, taps are for this purpose.

Using a tape in a hole that has a thread is fraught with risk of damage to that thread =.

Get yourself some Thread Chasers. These are for tidying up existing threads.

for the Block,

1/4" UNF (though, there's only the one of these)
5/16" UNF
3/8" UNC
7/16" UNF
There's also 1/8" NPT, but you're not likely to need that one and being a tapered Thread, you need to be careful,
and a couple of BSPP

On top of these, for the Head, you'll also want 5/16" UNC

[Peter Laidler]

Funny you should say that Spider Chris as I was always taught by our old and bold Apprentice masters clean-up bolt threads as opposed to re-cutting them with a tap. Since then I have allways had a multi sided double ended thread file in my file tray. Damaged external thread, ALWAYS try to clean it up first.

Mind you, how often have I just spun a die-nut down the shaft. The lazy way!

[Skeete]

Thanks very much Spider. I have never needed to actually tap a thread, its always been a cleanup job.
I was looking about at Tap sets and Baulked at the price, especially the Snap-on ones.

I also appreciate the specificity of the bolt size as well.
I didn't want to just buy a set that ranged in sizes and then find it doesn't cover what I need.

I think this should cover it.
https://www.walmart.com/ip/42Pcs-Rethre ... /343105399

But someone please let me know if it doesn't. Open to recommendations.

[Skeete]

I have a list of bolt sizes:
one list is more comprehensive but partly German - you'll need Google translate (N.B. LIMA is generator, not gonna find that in the dictionary)
The other list is limited to the engine, but in English.

Thanks very much MiNiKin. This is indeed very useful, and I do speak a little German so I can muddle my way through.

[Spider]

Peter,,, them old fellas that teach us this stuff,,,,, yeah,,,, they knew the right wheel barrow to push mate.

I've a thread file and it's got me out of a few binds when 'on safari'.

I too, probably like most of us have used taps and dies for thread cleaning and I have to say, I have come unstuck too doing that.

Thanks very much Spider. I have never needed to actually tap a thread, its always been a cleanup job.
I was looking about at Tap sets and Baulked at the price, especially the Snap-on ones.

I also appreciate the specificity of the bolt size as well.
I didn't want to just buy a set that ranged in sizes and then find it doesn't cover what I need.

I think this should cover it.
https://www.walmart.com/ip/42Pcs-Rethre ... /343105399

But someone please let me know if it doesn't. Open to recommendations.

No worries Skeete.

That set does seem to cover the sizes you need, just be sure it's decent quality. No good using a $5.00 tool only to damage a $10 000.00 part with it.

[GraemeC]

I have that set and find it is OK. I've not yet tried to restore a badly damaged thread with it, but it is great for cleaning and just easing ones that have got a little tight for some reason or other.

[Peter Laidler]

Yep, I see that the Walmart set has the multi sided thread files too. They understand my apprenticemasters advice too. ALWAYS try to repair an external thread first.

Good thread and good advice too.

[GTM71]

I was told the best thing is a new bolt of the correct size with 2 slots cut in it like a tap has. Wind it in and out, the slot collects the muck, but your thread is uncut. Tis what my old man taught me anyway.

[Exminiman]

For this purpose I would recommend against using taps.

Using a tap in a hole that has a thread is fraught with risk of damage to that thread

Get yourself some Thread Chasers. These are for tidying up existing threads.

Agree, thread chasers are what you should use to reshape thread rather than cut it (sure all of us use taps as well ) I have this set plus some odds and it works preety well for the occasional use i give it.

https://www.sealey.co.uk/product/563717 ... tricunfunc

Its a generic set probably from China as I have seen various manufactures names on it, but if you bang in the Sealey code AK311 into google , you can get it down to about £85

Might be a good start ?